The Brahmaputra, Irrawady and Mekong rivers originate in Tibet and flow though narrow and parallel mountain ranges in their upper reaches. Of these rivers, Brahmaputra makes a “U” turn in its course to flow into India. This “U” turn is due to
(a) Uplift of folded Himalayan series
(b) Syntaxial bending of geologically young Himalayas
(c) Geo-tectonic disturbance in the tertiary folded mountain chains
(d) Both (a) and (b) above